Computational 3-dimensional dislocation elastodynamics
Computational 3-dimensional dislocation elastodynamics
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DOI：
10.1016/j.jmps.2019.02.008
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发表时间：
2019-05
影响因子：
5.3
通讯作者：
Yinan Cui;G. Po;Y. Pellegrini;M. Lazar;N. Ghoniem
中科院分区：
文献类型：
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作者：
Yinan Cui;G. Po;Y. Pellegrini;M. Lazar;N. Ghoniem
了解固体在极高应变率下的力学行为具有重大的科学和技术意义。现有的基于位错的塑性力学模型多采用准静态方法。它们对高应变率条件的适用性有限，因为极端应变率下的弹性动力学应力场对三维（3D）位错集体行为的影响尚不清楚，并且当应变率高于10 6 s− 1（例如激光冲击加载）时，时间相关性非常重要。为了克服这一限制，我们在这里提出的第一个三维离散位错弹性动力学（DDE）的计算程序。本文提出了一种计算非均匀位错环弹性动力学场的新方法。这里开发的方法扩展了延迟电位技术，该技术最初用于描述带电粒子以接近光速移动的电动力学。与独立的二维计算比较，建立了数值方案的精度和收敛性。结果表明，位错环运动附近的声速的结果在显着的重组所发射的弹性动力学领域。通过对快速移动的剪切位错环之间的力的研究，还揭示了冲击加载过程中短时间位错相互作用的新见解。
Understanding the mechanical behavior of solids at extremely high strain rates is of great scientific and technical interest. Current dislocation-based model of plasticity are typically implemented as quasi-static method. Their applicability to high strain rate condition is limited, because the influence of the elastodynamic stress field at extreme strain rates on the collective behavior of 3-dimensional (3D) dislocations is not clear, and the time-dependent nature is very important when the strain rate is higher than 10 6 s− 1 (eg laser shock loading). To overcome this limitation, we present here the first computational procedure for 3D discrete dislocation elastodynamics (DDE). A novel computational method is developed for calculations of the fully-resolved elastodynamic field of non-uniformly moving dislocation loops. The developed method here extends the technique of retarded potentials, which was originally used to describe the electrodynamics of charged particles moving near the speed of light. Comparison with independent 2D calculations establish the accuracy and convergence of the numerical scheme. It is shown that dislocation loop motion near the sound speed results in significant restructuring of the emitted elastodynamic fields. New insights on short-time dislocation interactions during shock loading are also revealed through a study of the forces between rapidly-moving shear dislocation loops.